1. Field of the Invention
The invention relates to a vehicular drive system.
2. Description of Related Art
A temperature regulation system adapted to raise the oil temperature of a transmission is known. For example, a temperature regulation system for regulating the temperature of transmission oil is disclosed in Japanese Patent Application Publication No. 2007-85457 (JP 2007-85457 A). In this system, a heat-exchange pipe is installed in an oil pan of a transmission of an automobile, and engine oil that is led from a circulation system of engine oil is caused to flow through the heat-exchange pipe, so that the transmission oil is warmed by heat of the engine oil.
When heat is transferred from the engine oil to the oil of the transmission, loss of the transmission is reduced due to increase of the temperature of the transmission oil, whereas loss of the engine is increased due to reduction of the temperature of the engine oil. Thus, through the heat exchange, the overall loss as the sum of the loss of the engine and the loss of the transmission may be increased.